Sunday 31 August 2014

Pictures from Hailuoto

We are going to shamelessly ape the KAIRA blog and post not-so-scientific stuff once in a while especially on weekends. So for this Sunday we present some pictures from Hailuoto (map), an island near to Oulu, where I spent few days couple a weeks ago with Professor Markku Lehtinen in order to finalise our EISCAT3D reports.

It is an excellent place to retreat and to work without distractions.

Marjaniemi lighthouse and the former pilot station which is now a hotel and a restaurant.

Fisher boat on dry land

Sunset in Marjaniemi

Fishermen's huts. We rented two of those. No running water or bathrooms, but enough electricity for our computers.
All pictures by M.O.

Saturday 30 August 2014

Applied Inverse Problems 2015

A major inverse problems conference, Applied Inverse Problems, will be organised in Helsinki, Finland, May 25-29, 2015. The event website is at Important dates are:

  • Mini-symposium Proposal Deadline: September 30, 2014
  • Poster, Contributed Talk, and Minisymposium Talk Abstract Deadline: November 30, 2014
  • Calderon Prize Nomination Deadline: January 31, 2015
  • Early Bird Registration Deadline: February 11, 2015

Friday 29 August 2014

Quest for Beacon Satellites

SGO has been running a dual-frequency (150/400 MHz) tomography chain with ~5 stations in Fenno-Scandinavia since early 2000s. The chain relies on the Russian Tsykada navigation satellites, i.e. the COSMOS satellites. There is currently three COSMOS satellites with suitable operational transmitters. During recent years, Finnish Meteorological Institute (FMI) has carried out an ionospheric tomography project titled "TomoScand". For this project FMI, in collaboration with SGO, has developed a new beacon receiver  (GNU Ionospheric Tomography Receiver - Jitter). In addition to COSMOS satellites, with the new system we can receive any 150/400 MHz beacon, provided the satellite visibility. These satellites are currently the e-POP and DMSP F15. Hence, currently we have 5 satellites in the field-of-view of TomoScand and SGO chain.

Following the success of the TomoScand new receivers, we at SGO, are currently thinking of upgrading the SGO chain to the TomoScand receivers. However, this can be only done if we have enough satellites in the sky. (Enough means at least one, preferably more.) Hence, we have been searching for signs of continuity of the Tsykada mission and possible other missions. Following a Russian internet source, we have understood that there will a set of launches for COSMOS satellites during 2014-15.  (We do not know the launch dates.) Hence, I feel personally that if there is even one flying satellite, we can do science with that and thus it would be sensible to upgrade the system. However, as resources are limited, we need to think this thoroughly. We'll keep you updated on our plans in the near future.

If anyone has information on any new dual-fequency beacon satellite missions in the near future, which we could use for TomoScand, please let us know!

Thursday 28 August 2014

Physics seminar talk, Univ Oulu, 13:15

Today, in the main campus of the University of Oulu, Department of Physics at 13:15, I will talk in the space physics seminar series about my own research. I will concentrate on showing how we study geophysical experiments and data analysis as problems in applied mathematics.


Geophysical experiments and data analysis as problems in applied mathematics

We give a brief overview of the recent advances of the mathematical theory of ionospheric radar and tomography measurements and geophysical time-series analysis. We start by the comparison of measurements of radar experiments, which is the basic starting point for finding mathematical limits of radar experiments. Then we show how to use Gaussian Markov random fields and stable distributions as priors for Bayesian inversion and apply the developed methodology to ionospheric tomography. Experiment results of the new ionospheric tomography network "TomoScand" will be shown. Finally we proceed to the modern time-series analysis, the dynamic linear models and apply the methodology to Sodankylä ionosonde hmF2 analysis.

Wednesday 27 August 2014

The Northern Lights season starts in Lapland

The approaching autumn means also start of the season of the Northern Lights in Lapland and Finland. Past week, during a moderate geomagnetic storm (Kp max ~ 5 ), first aurora observations were reported from Central and Southern Finland in the Taivaanvahti observation system of the URSA (the Astronomical Association of Finland).

The all-sky imagers at SGO were switched on earlier this week. The first observation night, 25 August 2014, was clear and some minor auroras were visible in the northern horizon of the sky. The dark time is still short, but every night is about nine minutes longer than previous one. The all-sky camera starts operation, when the Sun is six degrees below horizon and the latest image is updated once per minute, when camera is in operation.

The starting season is 15th winter with present imager. Of course, some parts of the camera has been replaced, like the intensifier and data storing computer. The iCCD imager has three filters for  auroral spectral lines: 428.8 nm (blue), 557.7nm (green) and 630.0nm (red). The video is composition of the image sequence every minute. Note, the time is running fast making auroras more active than they are in reality. More movies about active northern light display (ie. 25 March 2014) can be browsed from SGO data server.

Sodankylä Geophysical Observatory has long tradition of automatic aurora imaging. Digital era of all-sky cameras started in 2000, when all-sky camera with photo tube intensifier and iCCD unit was bought. Before that film camera with spherical mirror were used for all sky imaging. SGO camera is part of the MIRACLE network. More details about the imagers can be found from MIRACLE website.

SGO has also EMCCD spectral imager, which operates in Abisko, Sweden to get better overlapping with the similar imager of FMI in Kilpisjärvi.

SGO hosts also All Sky Colour Imager of  APL, University College of London, UK. The main purpose of the imager is support for the Fabry-Perot Interferometer, which has been in operation since 2002.

According to FMI forecast coming nights seems to be cloudy. Waiting for clear skies...

Tuesday 26 August 2014

KAIRA spectral riometry paper out!

I'm happy to announce that our proof-of-concept study on the electron density profile estimation based on the KAIRA spectral riometry measurement has been finally published in the Geophysical Research Letters, please have a look:

Kero, A., J. Vierinen, D. McKay-Bukowski, C.-F. Enell, M. Sinor, L. Roininen, and Y. Ogawa (2014), Ionospheric electron density profiles inverted from a spectral riometer measurement, Geophys. Res. Lett., 41,  doi:10.1002/2014GL060986

By comparing our spectral riometry results to a simultaneous EISCAT VHF measurement, we were able to show that the methodology works, at least under conditions of relatively strong ionisation. This builds confidence towards continuous monitoring of height-dependent D-region ionisation by spectral riometry.

Monday 25 August 2014

Sodankylä Geophysical Observatory blog

We introduce a general Sodankylä Geophysical Observatory blog. This blog continues in the same path as the popular KAIRA blog, but the idea is to cover more widely the Observatory activities, including published papers, conference and workshop announcements, reporting on campaigns and extensive research visits, installation of new instruments etc. We will also use the blog for reporting sudden onset events. Naturally, we will also have some casual matters from time to time!

Welcome to read the blog! We intend to go for ~3 weblog postings per week!